1. Field of the Invention
The present invention relates to a swivelling guidewire extension system including an extension guidewire having a connecting assembly at the distal end thereof for releasably and firmly mechanically connecting with a thread connection to a proximal end of an initially inserted PTCA guidewire having a dilatation balloon catheter positioned thereon and situated within a guiding catheter inserted into a femoral artery or carotid artery, for enabling the dilatation balloon catheter to be removed and replaced with another dilatation balloon catheter.
2. Description of the Related Art Including Information Disclosed Under 37 CFR .sctn..sctn.1.97-1.99
Heretofore, it has been proposed to provide an exchange guidewire which, after removal of a shorter initially inserted guidewire, is inserted through a dilatation balloon catheter situated in a guiding catheter inserted in a femoral artery for the purpose of replacing the dilatation balloon catheter.
Since the procedure of utilizing an exchange guidewire is tedious, painstaking, time consuming and has some risk involved, it has also been proposed to utilize a guidewire extension for introducing a new dilatation catheter into a cardiovascular system.
For example, there is proposed in U.K. Patent Application No. 2 180 454 a guidewire system where the proximal end of an initially inserted guidewire is received in a sleeve which is also received over the distal end of an extension wire and the sleeve is crimped to fix the mating ends of the guidewire and extension wire together.
Also, an extendable guidewire system has been proposed in U.S. Pat. No. 4,827,941 wherein a small diameter proximal end portion of a primary or initial guidewire is frictionally received within a tubular member fixed to a distal end of a guidewire extension section.
Further, an extendable guidewire for introducing a dilatation catheter into a cardiovascular system has been proposed in U.S. Pat. No. 4,875,489 where the proximal end of a main guidewire has a tapered end portion which is received into a tubular member having a slit or slot therein which permits it to expand, the tubular member being received within an outer sleeve and fixed to a reduced in diameter distal end of a section of an auxiliary guidewire.
In U.S. Pat. No. 5,113,872 there is disclosed an extension guidewire system which includes an extension guidewire adapted to be releasably but firmly connected to the proximal end of an initial guidewire. The extension guidewire has a distal end and a proximal end, and the system further comprises a connecting assembly mounted at the distal end of the extension guidewire and includes a coiled spring constructed and arranged to receive and grippingly engage and lock against a distal end of the initial guidewire.
In U.S. Pat. No. 5,117,838 there is proposed a guidewire extension system which includes an extension guidewire adapted to be releasably but firmly connected to the proximal end of an initial guidewire. The extension guidewire has a distal end and a proximal end, and the system further comprises a connecting assembly which is mounted at the distal end of the extension guidewire, which includes a coiled spring constructed and arranged to receive and grippingly engage and lock against a distal end of the intial guidewire, and which includes a swivel joint for minimizing, if not eliminating, twisting of the extension guidewire when disconnecting the extension guidewire from the initial guidewire.
Further, a guidewire system for use in catheter exchanges is proposed in U.S. Pat. No. 5,197,486 which connects an extension wire to the proximal end of a guidewire to thereby increase the effective length of the guidewire to permit a catheter exchange. The proximal end of the guidewire is attached to the distal end of the exchange wire by a disconnectable, reattachable connection which avoids deformation of the connected joint. The connection includes a male element in the form of a reduced diameter rod extending axially from the proximal end of the guidewire and a female element attached to the distal end of the extension wire. The female element includes a helical coil receptive to the rod and dimensioned to receive the rod in an interference fit requiring the spring to expand. Separation is effected by imparting a combined twisting and axial separation motion to the guidewire and extension wire.
As will be described in greater detail hereinafter, the guidewire extension system of the present invention provides a simple connecting assembly including a coiled wire spring for quickly and firmly mechanically connecting (locking with a thread connection) the proximal end of an initially inserted guidewire to an extension guidewire and which permits quick and simple disengagement of the initially inserted guidewire from the connecting assembly.